The present invention relates to a substrate for reinforcement of elastomeric polymers wherein at least part of the substrate is made of steel. Steel wires and cords comprising steel wires twisted together (possibly together with other synthetic filaments such as aramid fibers) are often used for reinforcing rubber products such as tires, belts and hoses. In view of securing a proper and durable adhesion to the rubber, the wire surfaces are generally coated with an alloy layer such as brass or zinc.
Besides a proper adhesion capacity, the coating layer should preferably also protect the wires against corrosion attack. Indeed, corrosion of the reinforcing steel structure should always be avoided as the reinforcing effect decreases as a consequence of corrosion. Besides exposure of the steel elements to atmospheric corrosion before their embedment into rubber, corrosion attack is also possible after such embedment, especially when incisions in the rubber, which reach the wire surfaces, are produced.
Numerous efforts have been made up to now to design specific coating layers for steel wires which offer a good adhesion capacity (also after ageing of the reinforced composite) in combination with a proper corrosion resistance. Unfortunately, the application of those coating layers requires quite complicated processes which generally raise the production cost of the coated reinforcing material. Further, the coating process often becomes quite critical when steel wires are involved with elevated tensile strength e.g. over 3000 N/mm.sup.2, as those wires often require specific manufacturing processes.